WP7: How to Decompress an AES-256 Encrypted Zip File?

Question

I am trying to decompress an AES-256 encrypted zip file on Windows Phones 7 Application. How can that be accomplished?

Is there anyway to port C++ libraries or so in the current version of WP7? Any guide would be greatly appreciated.

Answer 1

AES256 is very compute intensive, this is why AES128 and lower is recommended for embedded (i.e. phone) development. You could find out that it takes 3 to 2 seconds to decrypt even a relativly small file.

Furthermore because of the complexity involved in implementing the algo, examples might only be found in C (at which point you'll have to port it)

http://www.codeproject.com/KB/security/aes.aspx

If you have access to web services while the application is running, then you could always write a web service (using framework 3.5 or 4) that accepts the encrypted file and returns the unencrypted, yet still compresed file; but yes worse case is that you'll have to port your own. If you do port your own please upload it on codeplex so that future persons can benifit :)

Answer 2

If you didn't have the AES encryption requirement you could use Silverlight SharpZipLib

There doesn't appear to be anything currently available which support AES-256. You may have to look at porting something yourself

Answer 3

It's possible to use the BouncyCastle library on WP7 with just a couple small modifications as noted here.